Technical characteristics of SNCR out of stock
The biggest difference between SNCR and SCR is that no catalyst is used in the process of denitration without causing SO2/SO3 oxidation, resulting in blockage of air preheater.
In the process of denitrification, there is no pressure loss in the process of SNCR denitrification, so it is not necessary to raise the pressure head of the fan. Especially, the remolding unit does not need to be reformed, which saves the investment and compresses the construction period.
The equipment required for SNCR is small, and is simple relative to the SCR equipment, the construction amount is reduced, the construction time is shortened, and it is more convenient for the project to be carried out in the case of large limit of site.
The whole process of SNCR reduction is carried out inside the boiler, and no reactor is needed. The reducing agent is sprayed into the flue gas through a nozzle installed on the boiler wall. The nozzle is arranged in the superheater area between the combustion chamber and the economizer, and the heat of the boiler provides energy for the reaction to restore the NOX here. The steel structure of the reactor and the reactor supported by the reactor and its subsidiary flue are cancelled, which reduces a large part of the investment, reduces most of the installation work, and facilitates the maintenance and maintenance work in the future.
The principle of SNCR denitration reaction
Under the condition of no catalyst at high temperature, the amino reducing agent (such as ammonia, ammonia water, urea) is injected into the furnace, and NH3 and other by-products are generated by pyrolysis. The selective non catalytic reduction reaction of NH3 and NOx in the flue gas is performed at 850-1100 C temperature window, and NOX is reduced to N2 and H20.
The first step is to generate reductant NH3, which is different from ammonia and ammonia. When urea is used as denitrification reducer, it needs to be pyrolyzed into NH3 first：
Second step NH3 and NOX reaction：